The most important thing to do is for you to be a peaceful, loving and
compassionate vegan as a witness before others. This sets an example.

How you approach others has a lot to do with circumstances and situation.
As an example, when someone wears fur, and you hear someone else compliment
them on their fur, you can join in and disagree, and say, "To me it's ugly,
because it makes the person look hard and uncaring about the suffering of
others." When it comes to food, it us also best to wait for something to be
said about the food, and then you can express the truth.

But remember, when responding always be polite, and if possible smile,
and never get angry.